Frozen aerated confections, such as ice cream, sorbet and frozen yoghurt contain many gas bubbles, typically 50 μm in diameter. The effectiveness of the gas bubbles is related to their size: generally, the smaller the bubbles, the smoother and creamier the texture. However, it is difficult to create and preserve gas bubbles with sizes of less than about 50 μm. This is because a dispersion of gas bubbles is vulnerable to coarsening by creaming, coalescence and disproportionation, resulting in fewer, larger bubbles. The smaller the gas bubbles (for a given total gas volume), the greater the driving force for coarsening.
EP 0 675 685 discloses frozen aerated confections containing gas bubbles having a D(3,2) average size of less than 20 μm, prepared by using sucrose esters. WO 98/09536 discloses a process for preparing frozen aerated confections having gas bubbles of less than 40 μm, by subjecting the product to shear forces and cooling in a screw extruder. US 2005/0037110 discloses ice cream which is mechanically treated by means of mechanical tools which generate large shear stresses, resulting in gas bubbles having a mean diameter of not more than 10 μm.
However, these routes require specialized ingredients or complex processing methods. Therefore, there remains a need for an improved, simple method for producing frozen aerated confections containing small gas bubbles.